Hydroprocessing of diesel range biomolecules

ABSTRACT

Non-hydrotreated biocomponent feeds can be mixed with mineral feeds and processed under catalytic isomerization/dewaxing conditions. The catalytic isomerization/dewaxing conditions can be selected to advantageously also substantially deoxygenate the mixed feed. Diesel fuel products with improved cold flow properties can be produced.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/339,795, filed Mar. 9, 2010, which is hereby incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

This invention relates to hydroprocessing of fuel feedstocks derivedfrom biocomponent sources, as well as hydroprocessing of blends ofbiocomponent and mineral fuel feedstocks.

BACKGROUND OF THE INVENTION

Biodiesel is gaining growing acceptance as a diesel fuel component.“Biodiesel” typically comprises fatty acid esters made from vegetableoil triglycerides, which can include various crops or waste oil, orother animal fats. Algae sources can also yield suitable triglycerides.The raw vegetable oil or animal fat triglycerides are reacted withalcohols such as methanol to form fatty acid alkyl esters specificallyto attain a viscosity within the diesel specification. A common type offatty acid alkyl ester is fatty acid methyl ester, or FAME. A separateASTM specification has issued that covers Biodiesel (D6751-07) whenblended with conventional diesel, but some of the specifications are notconsistent with conventional diesel specifications required for themixed blend. For example, the biodiesel Cloud Point specification isshown as “report only”, with a footnote that it is usually higher thanconventional diesel fuel and that this need to be taken intoconsideration. Biodiesel fuels often have relatively high cloud points.As a result, blends of biodiesel and conventional diesel may render thetotal blend unsuitable in terms of cloud point and/or other cold flowproperties.

European Patent Application Nos. EP 1741767 and EP 1741768 each describemethods for hydroprocessing diesel range feeds based on biocomponentsources, such as vegetable or animal fats/oils. The hydroprocessingmethods include exposing the biocomponent feed to hydrotreatingconditions, followed by a hydroprocessing step for isomerizing the feed.Isomerization catalysts identified in these publications includeSAPO-11, SAPO-41, ZSM-22, ZSM-23, and ferrierite. The isomerizationcatalysts are described as also including a Group VIII metal such as Ptand a binder such as alumina. The lowest cloud points identified in thereferences are between −14° C. and −22° C. The levels of n-paraffinsremaining in the isomerized diesel products were not specified.

U.S. Published Patent Application No. 2007/0006523 describes methods forproducing diesel fuels from a Tall Oil Fatty Acid (TOFA) fraction. TheTOFA fraction is described as including triglycerides present inbiocomponent feeds, such as rapeseed oil, sunflower oil, or palm oil.The methods include hydrotreatment, followed by isomerization. The mostsuitable isomerization catalysts are described as catalysts with lowacidity. SAPO-11 bound with alumina and ZSM-22 or ZSM-23 bound withalumina are provided as examples of isomerization catalysts. Theisomerization catalyst is also described as including a supported GroupVIII metal such as Pt. No cloud points are provided for the diesel fuelproducts. The lowest reported number for the amount of n-paraffins in anisomerized product is 13%.

U.S. Published Patent Application No. 2006/0207166 describes methods forhydroprocessing biocomponent feeds in a single step. The single stepperforms both hydrodeoxygenation and hydroisomerization. The catalystfor the single step is described as including both a metal component andan acidic component. The metal component is described as platinum orpalladium. A wide variety of zeolites are described for the acidiccomponent. A porous solid support may also be present. The lowest cloudpoints reported for diesel fuels made according to the process describedin this publication are between −11° C. and −16° C. A cloud point below−20° C. is also reported in a comparative example. After processing, thereported diesel products had n-paraffin contents of at least 14.5%.

U.S. Published Patent Application No. 2009/0019763 describes a methodfor treating mixtures of vegetable oil and mineral feed with a catalystunder hydrotreating conditions. The catalyst can include cobalt andmolybdenum supported on a dealuminated form of ZSM-5.

International Application No. PCT/US2008/012516 describes methods fortreating a biocomponent feedstock by first hydrotreating the feed andthen dewaxing the feed under catalytic dewaxing conditions. The dewaxingcatalyst can be a ZSM-48 containing catalyst that includes platinum.

What is needed is a method for producing biocomponent based diesel fuelswith improved properties to facilitate use in the commercial fuelsupply. Preferably, the method would allow for production of dieselfuels that satisfy any current cold flow property requirements whilealso providing improved cetane.

SUMMARY OF THE INVENTION

One aspect of the invention relates to a method for producing a dieselfuel, comprising: mixing a biocomponent feed portion having an oxygencontent of at least about 8 wt % with a mineral feed portion to form acombined feedstock, the combined feedstock having a sulfur content ofless than about 50 wppm and a nitrogen content of less than about 20wppm, the biocomponent feed portion being at least about 5 wt % of thecombined feedstock; and contacting the combined feedstock with anisomerization/dewaxing catalyst, the isomerization/dewaxing catalystcomprising (i) a molecular sieve selected from ZSM-23, ZSM-48, and acombination thereof and having a silica to alumina ratio of about 90:1or less, and (ii) a hydrogenation metal, under effectiveisomerization/dewaxing conditions including a temperature of at leastabout 350° C. and being effective to remove about 99% of the oxygencontent of the combined feed and to produce an isomerized/dewaxedproduct having a cloud point of about −20° C. or less.

Another aspect of the invention relates to a method for producing adiesel fuel, comprising: mixing a biocomponent feed portion having anoxygen content of at least about 8 wt % with a mineral feed portion toform a combined feedstock, the biocomponent feed portion being at leastabout 5 wt % of the combined feedstock; and contacting the combinedfeedstock with an isomerization/dewaxing catalyst, theisomerization/dewaxing catalyst comprising (i) a molecular sieveselected from Beta, USY, ZSM-5, ZSM-35, ZSM-23, ZSM-48, and acombination thereof and (ii) at least about 2 wt % of a Group VIIIhydrogenation metal selected from Ni and/or Co plus at least about 10 wt% of a Group VIB hydrogenation metal selected from Mo and/or W, undereffective isomerization/dewaxing conditions including a temperature ofat least about 350° C. and being effective to remove about 99% of theoxygen content of the combined feed and to produce an isomerized/dewaxedproduct having a cloud point of about −20° C. or less.

Yet another aspect of the invention relates to a method for producing adiesel fuel, comprising: mixing a biocomponent feed portion with amineral feed portion to form a combined feedstock, the combinedfeedstock having a sulfur content of less than about 50 wppm and anitrogen content of less than about 20 wppm, the biocomponent feedportion containing triglycerides, being substantially free of ketones,and having an oxygen content of at least about 8 wt %, the biocomponentfeed portion being at least about 5 wt % of the combined feedstock; andcontacting the combined feedstock with an isomerization/dewaxingcatalyst comprising at least 0.5 wt % of Pt as a hydrogenation metal andZSM-48 having a silica to alumina ratio of about 90:1 or less, undereffective isomerization and/or dewaxing conditions including atemperature of at least about 350° C. and being effective to removeabout 99% of the oxygen in the combined feed and to produce a dewaxedproduct having a cloud point of about −20° C. or less, wherein theisomerized and/or dewaxed product exhibits a peak characteristic of aketone in an infrared spectrum between about 1700 cm⁻¹ and about 1725cm⁻¹.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a reaction system suitable for performing a processaccording to the invention.

FIG. 2 shows cloud point data for a variety of feeds processed under avariety of test conditions.

FIGS. 3 a and 3 b show portions of an infrared spectrum for a productmade according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In an embodiment, mixtures of a biocomponent feed and a mineral feed canbe treated under hydroprocessing conditions to produce a diesel fuelwith beneficial cold flow properties. For example, a mixture of at least5 wt % of a non-hydrotreated biocomponent feed portion can be combinedwith a mineral feed portion to form a diesel boiling range feedstock.The combined diesel range feedstock can be exposed to anisomerization/dewaxing catalyst that includes a Group VIII metal, suchas Pt or Ni, and optionally (e.g., usually when the Group VIII metal isNi or the like) a Group VIB metal, such as Mo and/or W. Preferably, thebase of the isomerization/dewaxing catalyst can include a molecularsieve, such as a zeolite with a suitable ratio of silicon to aluminum(e.g., expressed in the common oxide forms, namely silica to alumina,sometimes abbreviated as Si/Al₂) in the zeolite. The combined dieselrange feedstock can be exposed to the isomerization/dewaxing catalystunder effective catalytic isomerization and/or dewaxing conditions. Thiscan result in a diesel boiling range product with improved cold flowproperties, particularly at least improved (or higher) cloud point, andthat is suitable for use as a diesel fuel. Additionally or alternately,either the combined feedstock or one or both of the individual feedstockportions can optionally be hydrotreated prior to isomerization/dewaxing.Also additionally or alternately, the feedstock can optionally behydrofinished after isomerization/dewaxing.

One potential use for the methods according to the invention is to makeuse of “winter diesel” processing capacity during warmer months. Typicaldiesel fuels may not be suitable for climates where winter months haveextreme cold temperatures, such as −20° C. or lower. To avoiddifficulties with cold temperature flow, diesel fuel with improved lowtemperature properties can be manufactured. One method for making such“winter diesel” is to use an isomerization process, such as catalyticdewaxing, to isomerize a diesel fuel.

The isomerization unit used for making winter diesel could be usedduring warmer months for additional production of biodiesel, thusincreasing refinery utilization. Isomerization can be beneficial fordiesel fuels based on biocomponent sources. While diesel fuels based ona biocomponent feed may tend to have higher cetane rating than a mineraldiesel feed, the cloud point temperature and other cold flow propertiesof a biocomponent based diesel fraction are typically not as favorable.Isomerization of a biocomponent diesel fraction can allow the increasedcetane value of the biocomponent fraction to be added to the diesel fuelpool, while mitigating any loss in cold flow properties, particularly incloud point.

Feedstocks

In the discussion below, a “mineral oil” feedstock is meant to be ahydrocarbon-based oil from a fossil/mineral fuel source, such as crudeoil, and not the commercial organic product, such as sold under CASnumber 8020-83-5, e.g., by Aldrich.

In the discussion below, a biocomponent feedstock refers to ahydrocarbon feedstock derived from a biological raw material component,from biocomponent sources such as vegetable, animal, fish, and/or algae.Note that, for the purposes of this document, vegetable fats/oils refergenerally to any plant based material, and can include fat/oils derivedfrom a source such as plants of the genus Jatropha. Generally, thebiocomponent sources can include vegetable fats/oils, animal fats/oils,fish oils, pyrolysis oils, and algae lipids/oils, as well as componentsof such materials, and in some embodiments can specifically include oneor more type of lipid compounds. Lipid compounds are typicallybiological compounds that are insoluble in water, but soluble innonpolar (or fat) solvents. Non-limiting examples of such solventsinclude alcohols, ethers, chloroform, alkyl acetates, benzene, andcombinations thereof.

Major classes of lipids include, but are not necessarily limited to,fatty acids, glycerol-derived lipids (including fats, oils andphospholipids), sphingosine-derived lipids (including ceramides,cerebrosides, gangliosides, and sphingomyelins), steroids and theirderivatives, terpenes and their derivatives, fat-soluble vitamins,certain aromatic compounds, and long-chain alcohols and waxes.

In living organisms, lipids generally serve as the basis for cellmembranes and as a form of fuel storage. Lipids can also be foundconjugated with proteins or carbohydrates, such as in the form oflipoproteins and lipopolysaccharides.

Examples of vegetable oils that can be used in accordance with thisinvention include, but are not limited to rapeseed (canola) oil, soybeanoil, coconut oil, sunflower oil, palm oil, palm kernel oil, peanut oil,linseed oil, tall oil, corn oil, castor oil, jatropha oil, jojoba oil,olive oil, flaxseed oil, camelina oil, safflower oil, babassu oil,tallow oil, and rice bran oil.

Vegetable oils as referred to herein can also include processedvegetable oil material. Non-limiting examples of processed vegetable oilmaterial include fatty acids and fatty acid alkyl esters. Alkyl esterstypically include C₁-C₅ alkyl esters. One or more of methyl, ethyl, andpropyl esters are preferred.

Examples of animal fats that can be used in accordance with theinvention include, but are not limited to, beef fat (tallow), hog fat(lard), turkey fat, fish fat/oil, and chicken fat. The animal fats canbe obtained from any suitable source including restaurants and meatproduction facilities.

Animal fats as referred to herein also include processed animal fatmaterial. Non-limiting examples of processed animal fat material includefatty acids and fatty acid alkyl esters. Alkyl esters typically includeC₁-C₅ alkyl esters. One or more of methyl, ethyl, and propyl esters arepreferred.

Algae oils or lipids are typically contained in algae in the form ofmembrane components, storage products, and metabolites. Certain algalstrains, particularly microalgae such as diatoms and cyanobacteria,contain proportionally high levels of lipids. Algal sources for thealgae oils can contain varying amounts, e.g., from 2 wt % to 40 wt % oflipids, based on total weight of the biomass itself.

Algal sources for algae oils include, but are not limited to,unicellular and multicellular algae. Examples of such algae include arhodophyte, chlorophyte, heterokontophyte, tribophyte, glaucophyte,chlorarachniophyte, euglenoid, haptophyte, cryptomonad, dinoflagellum,phytoplankton, and the like, and combinations thereof. In oneembodiment, algae can be of the classes Chlorophyceae and/or Haptophyta.Specific species can include, but are not limited to, Neochlorisoleoabundans, Scenedesmus dimorphus, Euglena gracilis, Phaeodactylumtricornutum, Pleurochrysis carterae, Prymnesium parvum, Tetraselmischui, and Chlamydomonas reinhardtii.

The biocomponent feeds usable in the present invention can include anyof those which comprise primarily triglycerides and free fatty acids(FFAs). The triglycerides and FFAs typically contain aliphatichydrocarbon chains in their structure having from 8 to 36 carbons,preferably from 10 to 26 carbons, for example from 14 to 22 carbons.Types of triglycerides can be determined according to their fatty acidconstituents. The fatty acid constituents can be readily determinedusing Gas Chromatography (GC) analysis. This analysis involvesextracting the fat or oil, saponifying (hydrolyzing) the fat or oil,preparing an alkyl (e.g., methyl) ester of the saponified fat or oil,and determining the type of (methyl) ester using GC analysis. In oneembodiment, a majority (i.e., greater than 50%) of the triglyceridepresent in the lipid material can be comprised of C₁₀ to C₂₆ fatty acidconstituents, based on total triglyceride present in the lipid material.Further, a triglyceride is a molecule having a structure substantiallyidentical to the reaction product of glycerol and three fatty acids.Thus, although a triglyceride is described herein as being comprised offatty acids, it should be understood that the fatty acid component doesnot necessarily contain a carboxylic acid hydrogen. In one embodiment, amajority of triglycerides present in the biocomponent feed canpreferably be comprised of C₁₂ to C₁₈ fatty acid constituents, based ontotal triglyceride content. Other types of feed that are derived frombiological raw material components can include fatty acid esters, suchas fatty acid alkyl esters (e.g., FAME and/or FAEE).

In an embodiment, the biocomponent portion of the feedstock can includeat least about 5% by weight of glycerides (e.g., monoglycerides,diglycerides, triglycerides, or the like, or combinations thereof),fatty acid alkyl esters, or a combination thereof, for example at leastabout 10 wt % or at least 20 wt %. Additionally or alternately, thebiocomponent portion of the feedstock can include about 55 wt % or lessof glycerides, fatty acid alkyl esters, or a combination thereof, forexample about 50 wt % or less, about 45 wt % or less, about 40 wt % orless, about 35 wt % or less, about 30 wt % or less, about 25 wt % orless, or about 20 wt % or less. Preferably, the biocomponent portion ofthe feedstock can include triglycerides and/or fatty acid methyl esters.

In a preferred embodiment, the biocomponent portion of the feedstock(such as the triglycerides and/or fatty acid methyl esters) can be anon-hydrotreated portion. A non-hydrotreated biocomponent feed cantypically have an olefin content and an oxygen content similar to thatof the corresponding raw biocomponent material. Examples of suitablenon-hydrotreated biocomponent feeds can include, but are not limited to,food-grade vegetable oils and biocomponent materials that are refined,bleached, and/or deodorized.

Biocomponent based diesel boiling range feedstreams typically haverelatively low nitrogen and sulfur contents. Instead of nitrogen and/orsulfur, the primary heteroatom component in biocomponent feeds isoxygen. Biocomponent diesel boiling range feedstreams, e.g., can includeup to about 10 wt % oxygen, up to about 12 wt % oxygen, or up to about14 wt % oxygen. Suitable biocomponent diesel boiling range feedstreams,prior to hydrotreatment, can include at least about 5 wt % oxygen, forexample at least about 8 wt % oxygen. A biocomponent feedstream, priorto hydrotreatment, can include an olefin content of at least about 3 wt%, for example at least about 5 wt % or at least about 10 wt %.

A mineral hydrocarbon feedstock refers to a hydrocarbon feedstockderived from crude oil that has optionally but preferably been subjectedto one or more separation and/or other refining processes. Preferably,the mineral hydrocarbon feedstock is or includes a petroleum feedstockboiling in the diesel range or above. Examples of suitable feedstockscan include, but are not limited to, virgin distillates, kerosene,diesel boiling range feeds, jet fuel, light cycle oils, and the like,and combinations thereof, including hydrotreated versions thereof.

Mineral feedstreams for blending with a biocomponent feedstream can havea nitrogen content from about 50 wppm to about 2000 wppm, preferablyfrom about 50 wppm to about 1500 wppm, for example from about 75 wppm toabout 1000 wppm. Additionally or alternately, feedstreams suitable foruse herein can have a sulfur content from about 100 wppm to about 10000wppm, for example from about 200 wppm to about 5000 wppm or from about350 wppm to about 2500 wppm. Further additionally or alternately, thecombined biocomponent and mineral feedstock can have a sulfur content ofat least about 5 wppm, for example at least about 10 wppm, at leastabout 25 wppm, at least about 100 wppm, at least about 300 wppm, atleast about 500 wppm, or at least about 1000 wppm. Independently and/orin this further embodiment, the combined feedstock can have a sulfurcontent of about 2000 wppm or less, for example about 1000 wppm or less,about 500 wppm or less, about 300 wppm or less, about 100 wppm or less,or about 50 wppm or less. Still further additionally or alternately, thenitrogen content of the combined feedstock can be about 1000 wppm orless, for example about 500 wppm or less, about 300 wppm or less, about100 wppm or less, about 50 wppm or less, about 30 wppm or less, or about10 wppm or less.

In some embodiments, an isomerization/dewaxing catalyst can be used thatincludes the sulfide form of a metal, such as an isomerization/dewaxingcatalyst that includes nickel and tungsten. In such embodiments, it canbe beneficial for the combined mineral and biocomponent feed to have atleast a minimum sulfur content. The minimum sulfur content can besufficient to maintain the sulfided metals of the isomerization/dewaxingcatalyst in a sulfided state. For example, the combined mineral andbiocomponent feedstock can have a sulfur content of at least about 50wppm, for example at least about 100 wppm, at least about 150 wppm, orat least about 200 wppm. Additionally or alternately, the combinedmineral and biocomponent feedstock can have a sulfur content of about500 wppm or less, for example about 400 wppm or less or about 300 wppmor less. In any of these embodiments, the additional sulfur to maintainthe metals of the isomerization/dewaxing catalyst in a sulfided statecan be provided by gas- and/or liquid-phase sulfur, such as gas-phaseH₂S. One potential source of H₂S gas can be from hydrotreatment of themineral portion of a feedstock. If a mineral feed portion ishydrotreated prior to combination with a biocomponent feed, at least aportion of the gas phase effluent from the hydrotreatment process/stage,particularly containing sufficient H₂S gas, can be cascaded along withhydrotreated liquid effluent.

The content of sulfur, nitrogen, oxygen, and olefins in a feedstockcreated by blending two or more feedstocks can typically be determinedusing a weighted average based on the blended feeds. For example, amineral feed and a biocomponent feed can be blended in a ratio of 80 wt% mineral feed and 20 wt % biocomponent feed. If the mineral feed has asulfur content of about 1000 wppm, and the biocomponent feed has asulfur content of about 10 wppm, the resulting blended feed could beexpected to have a sulfur content of about 802 wppm.

Diesel boiling range feedstreams suitable for use in the presentinvention tend to boil within the range of about 215° F. (about 102° C.)to about 800° F. (about 427° C.). Preferably, the diesel boiling rangefeedstream has an initial boiling point of at least about 215° F. (about102° C.), for example at least about 250° F. (about 121° C.), at leastabout 275° F. (about 135° C.), at least about 300° F. (about 149° C.),at least about 325° F. (about 163° C.), at least about 350° F. (about177° C.), at least about 400° F. (about 204° C.), or at least about 451°F. (about 233° C.). Preferably, the diesel boiling range feedstream hasa final boiling point of about 800° F. (about 427° C.) or less, or about775° F. (about 413° C.) or less, or about 750° F. (about 399° C.) orless. In an embodiment, the diesel boiling range feedstream has aboiling range from about 451° F. (about 233° C.) to about 800° C. (about427° C.). Additionally or alternately, the feedstock can becharacterized by the boiling point required to boil a specifiedpercentage of the feed. For example, the temperature required to boil atleast 5 wt % of a feed is referred to as a “T5” boiling point. In oneembodiment, the mineral oil feedstock can have a T5 boiling point of atleast about 230° F. (about 110° C.), for example at least about 250° F.(about 121° C.) or at least about 275° F. (about 135° C.). Furtheradditionally or alternately, the mineral hydrocarbon feed can have a T95boiling point of about 775° F. (about 418° C.) or less, for exampleabout 750° F. (about 399° C.) or less or about 725° F. (about 385° C.)or less. In another embodiment, the diesel boiling range feedstream canalso include kerosene range compounds to provide a feedstream with aboiling range from about 250° F. (about 121° C.) to about 800° F. (about427° C.).

In certain embodiments, for example where a feed is delivered to anisomerization/dewaxing stage without prior treatment to remove sulfurand/or nitrogen contaminants and/or where the isomerization/dewaxingstage contains a catalyst that does not include a sulfided form (e.g.,including a metal or metallic state or an oxide state), additionalbenefits can be achieved by selecting a feed with relatively low sulfurcontent and relatively low nitrogen content. In such embodiments, thesulfur content of the feed to the dewaxing stage can advantageously beless than 10 wppm, preferably less than 5 wppm, for example less than 3wppm. Additionally or alternately, in such embodiments, the nitrogencontent of the feed to the isomerization/dewaxing stage canadvantageously be less than 10 wppm, preferably less than 5 wppm, forexample less than 3 wppm.

Hydroprocessing—Isomerization/Dewaxing

Catalytic dewaxing relates to the removal and/or isomerization of longchain, paraffinic molecules from feeds. Catalytic dewaxing can beaccomplished by selective hydrocracking or by hydroisomerizing theselong chain molecules. Hydroisomerization/hydrodewaxing catalysts caninclude molecular sieves such as crystalline aluminosilicates (zeolites)and/or silicoaluminophosphates (SAPOs). In an embodiment, the molecularsieve can be a 1-D or 3-D molecular sieve. In another embodiment, themolecular sieve can be a 10-member ring 1-D molecular sieve (e.g.,ZSM-48). Examples of molecular sieves can include, but are not limitedto, ZSM-48, ZSM-23, ZSM-35, Beta, USY, ZSM-5, and combinations thereof.In an embodiment, the molecular sieve can include or be ZSM-48, ZSM-23,or a combination thereof. The isomerization/dewaxing catalyst canoptionally include a binder, such as alumina, titania, silica,silica-alumina, zirconia, or a combination thereof. In an embodiment,the binder can include or be alumina, titania, or a combination thereof.In another embodiment, the binder can include or be titania, silica,zirconia, or a combination thereof One feature of molecular sieves thatcan impact the activity of the molecular sieve is the ratio of siliconto aluminum in the molecular sieve (expressed generally in the oxideform as silica to alumina). For instance, the molecular sieve canadvantageously have a silica to alumina ratio of about 200 to 1 or less,preferably about 120 to 1 or less, for example about 100 to 1 or less,about 90 to 1 or less, or about 75 to 1 or less. Additionally oralternately, the molecular sieve can advantageously have a silica toalumina ratio of at least about 30 to 1, for example at least about 50to 1 or at least about 65 to 1.

The isomerization/dewaxing catalyst can also include a metalhydrogenation component, such as a Group VIII metal. Suitable Group VIIImetals can include, but are not limited to, Pt, Pd, Ni, and combinationsthereof. The isomerization/dewaxing catalyst can advantageously includeat least about 0.1 wt % of the Group VIII metal, for example at leastabout 0.3 wt %, at least about 0.5 wt %, at least about 1.0 wt %, atleast about 2.0 wt %, at least about 2.5 wt %, at least about 3.0 wt %,or at least about 5.0 wt %. Additionally or alternately, theisomerization/dewaxing catalyst can include about 10.0 wt % or less of aGroup VIII metal, for example about 7.0 wt % or less, about 5.0 wt %less, about 3.0 wt % or less, about 2.5 wt % or less, about 2.0 wt % orless, or about 1.5 wt % or less.

In some embodiments, particularly when Group VIII metal is a non-noblemetal such as Ni, the isomerization/dewaxing catalyst may additionallyinclude a Group VIB metal, such as W and/or Mo. For instance, in oneembodiment, the isomerization/dewaxing catalyst can include Ni and W, Niand Mo, or a combination of Ni, Mo, and W. In certain such embodiments,the isomerization/dewaxing catalyst can include at least about 0.5 wt %of the Group VIB metal, for example at least about 1.0 wt %, at leastabout 2.0 wt %, at least about 2.5 wt %, at least about 3.0 wt %, atleast about 4.0 wt %, or at least about 5.0 wt %. Additionally oralternately, the isomerization/dewaxing catalyst can include about 20.0wt % or less of a Group VIB metal, for example about 15.0 wt % or less,about 12.0 wt % or less, about 10.0 wt % or less, about 8.0 wt % orless, about 5.0 wt % or less, about 3.0 wt % or less, or about 1.0 wt %or less. In one particular embodiment, the isomerization/dewaxingcatalyst can include only a Group VIII metal selected from Pt, Pd, and acombination thereof.

Catalytic dewaxing can be performed by exposing a feedstock to adewaxing catalyst (that may, and usually does, also have isomerizationactivity) under effective (catalytic) dewaxing (and/or isomerization)conditions. Effective dewaxing (and/or isomerization) conditions caninclude, but are not limited to, a temperature of at least about 500° F.(about 260° C.), for example at least about 550° F. (about 288° C.), atleast about 600° F. (about 316° C.), or at least about 650° F. (about343° C.). Additionally or alternately, the temperature can be about 750°F. (about 399° C.) or less, for example about 700° F. (about 371° C.) orless, or about 650° F. (about 343° C.) or less. Effective dewaxing(and/or isomerization) conditions can additionally or alternatelyinclude, but are not limited to, a total pressure of at least about 400psig (about 2.8 MPag), for example at least about 500 psig (about 3.4MPag), at least about 750 psig (about 5.2 MPag), or at least about 1000psig (about 6.9 MPag). Additionally or alternately, the total pressurecan be about 1500 psig (about 10.3 MPag) or less, for example about 1200psig (about 8.2 MPag) or less, about 1000 psig (about 6.9 MPag) or less,or about 800 psig (about 5.5 MPag) or less. Effective dewaxing (and/orisomerization) conditions can additionally or alternately include, butare not limited to, a liquid hourly space velocity (LHSV) of at leastabout 0.5 hr⁻¹, for example at least about 1.0 hr⁻¹, at least about 1.5hr⁻¹, or at least about 2.0 hr⁻¹. Additionally or alternately, the LHSVcan be about 10 hr⁻¹ or less, for example about 5.0 hr⁻¹ or less, about3.0 hr⁻¹ or less, or about 2.0 hr⁻¹ or less. Effective dewaxing (and/orisomerization) conditions can additionally or alternately include, butare not limited to, a treat gas rate of at least about 500 scf/bbl(about 84 Nm³/m³), for example at least about 750 scf/bbl (about 130Nm³/m³) or at least about 1000 scf/bbl (about 170 Nm³/m³). Additionallyor alternately, the treat gas rate can be about 3000 scf/bbl (about 510Nm³/m³) or less, for example about 2000 scf/bbl (about 340 Nm³/m³) orless, about 1500 scf/bbl (about 250 Nm³/m³) or less, or about 1250scf/bbl (about 210 Nm³/m³) or less.

A catalytic dewaxing process can modify a feedstock in several ways. Thecatalytic dewaxing process can remove oxygen in the biocomponent portionof the feedstock. Olefins in the feedstock can also be at leastpartially saturated. The dewaxing process can also improve one or morecold flow properties of the feed, such as pour point and cloud point.Optionally, some sulfur and/or nitrogen removal may also occur.

Typical mineral distillate feeds suitable for conversion into a dieselfuel product can have initial cloud points ranging from about −20° C. toabout 5° C. The initial cloud point of biocomponent feeds can be higherstill, including feeds with an initial cloud point of up to about 20° C.In order to form a suitable diesel fuel product, catalytic dewaxing(and/or isomerization) conditions can be selected to reduce the cloudpoint by at least about 10° C., for example by at least about 20° C., byat least about 30° C., by at least about 40° C., or by at least about50° C.

Deoxygenating a feed can avoid problems with catalyst poisoning ordeactivation due to the creation of water or carbon oxides duringhydroprocessing. The catalytic isomerization/dewaxing process can beused to substantially deoxygenate a feedstock. This corresponds toremoving at least 90%, for example at least 95%, at least 98%, at least99%, at least 99.5%, at least 99.9%, or completely (measurably) all ofthe oxygen present in the biocomponent feedstock. Alternately,substantially deoxygenating the feedstock can correspond to reducing theoxygenate level of the total feedstock to 0.1 wt % or less, for example0.05 wt % or less, 0.03 wt % or less, 0.02 wt % less, 0.01 wt % or less,0.005 wt % or less, 0.003 wt % or less, 0.002 wt % or less, or 0.001 wt% or less.

Hydroprocessing—Hydrotreating and Hydrofinishing

In some embodiments, additional hydroprocessing can be performed beforeor after the catalytic dewaxing. Prior to isomerization/dewaxing, afeedstock can sometimes be hydrotreated. A hydrotreatment process canremove heteroatoms, such as oxygen, sulfur, and nitrogen from afeedstock. A hydrotreatment process can also saturate olefins. Such ahydrotreatment process can be used according to the invention with amineral portion of the combined feed, e.g., separately before additionto the biocomponent portion.

A hydrotreatment catalyst can contain at least one of Group VIB and/orGroup VIII metals, optionally on a support such as alumina or silica.Examples can include, but are not limited to, NiMo, CoMo, and NiWsupported catalysts. Hydrotreating conditions can be selected to besimilar to the isomerization/dewaxing conditions noted above.Alternately, the hydrotreating conditions can include, but are notnecessarily limited to, a temperature of about 315° C. to about 425° C.,a total pressure of about 300 psig (about 2.1 MPag) to about 3000 psig(about 21 MPag), an LHSV of about 0.2 hr⁻¹ to about 10 hr⁻¹, and ahydrogen treat gas rate of about 500 scf/bbl (about 84 Nm³/m³) to about10000 scf/bbl (about 1700 Nm³/m³).

During hydrotreatment, the sulfur and nitrogen contents of a feedstockcan advantageously be reduced. In an embodiment, the hydrotreatmentstage(s) can preferably reduce the sulfur content to a suitable level,such as less than about 100 wppm, for example less than about 50 wppm,less than about 30 wppm, less than about 25 wppm, less than about 20wppm, less than about 15 wppm, or less than about 10 wppm. In anotherembodiment, the hydrotreating stage(s) can reduce the sulfur content ofthe feed to less than about 5 wppm, for example less than about 3 wppm.With regard to nitrogen, the hydrotreating stage(s) can preferablyreduce the nitrogen content of the feed to about 30 wppm or less, about25 wppm or less, about 20 wppm or less, about 15 wppm or less, about 10wppm or less, about 5 wppm or less, or about 3 wppm or less. If ahydrotreatment process is performed before catalyticisomerization/dewaxing, some or all of the deoxygenation (and optionallybut preferably of the olefin saturation) described above can take placeduring the hydrotreating process.

If a hydrotreatment stage is used prior to isomerization/dewaxing, aseparation device can be used to separate out impurities prior topassing the hydrotreated feedstock to the isomerization/dewaxing stage.The separation device can be a separator, a stripper, a fractionator, oranother device suitable for separating gas phase products from liquidphase products. For instance, a separator stage can be used to remove atleast a portion of any H₂S and/or NH₃ formed during hydrotreatment,e.g., with the remainder of the H₂S and/or NH₃ formed duringhydrotreatment being cascaded to the isomerization/dewaxing stage, asdesired. Alternately, the entire effluent from the hydrotreatment stagecan be cascaded to the isomerization/dewaxing stage, if desired. Itshould be noted that the H₂S, when provided to an isomerization/dewaxingstage using a catalyst comprising both Group VIII and Group VIBhydrogenation metals, is believed to facilitate the maintenance ofsulfidation of the hydrogenation metals, e.g., in order to help thecatalyst retain its isomerization/dewaxing or other catalytic activity.

After isomerization/dewaxing, the isomerized/dewaxed feedstock can behydrofinished. A hydrofinishing stage can be similar to a hydrotreatingstage. For example, hydrofinishing can be a mild hydrotreating directedto saturating any remaining olefins and/or residual aromatics. Apost-isomerization/dewaxing hydrofinishing can be carried out in cascadewith the isomerization/dewaxing step. A hydrofinishing stage can operateat temperatures from about 150° C. to about 350° C., for example fromabout 180° C. to about 250° C. Total pressures in the hydrofinishingstage can be from about 400 psig (about 2.9 MPag) to about 3000 psig(about 20.8 MPag). Liquid hourly space velocities in the hydrofinishingstage can be from about 0.1 hr⁻¹ to about 5 hr⁻¹, for example from about0.5 hr⁻¹ to about 3 hr⁻¹. Hydrogen treat gas rates in the hydrofinishingstage can be from about 250 scf/bbl (about 42 Nm³/m³) to about 10,000scf/bbl (about 1700 Nm³/m³).

Suitable catalysts for hydrofinishing can include hydrotreatingcatalysts. Alternately, a hydrofinishing or aromatic saturation catalystcan be used, such as a Group VIII and/or Group VIB metal supported on abound support from the M41S family, such as bound MCM-41. Suitablebinders for a support from the M41S family, such as MCM-41, can includealumina, silica, or any other binder or combination of binders that canprovide a relatively high productivity and/or relatively low densitycatalyst. One example of a suitable aromatic saturation catalyst is analumina bound mesoporous MCM-41 modified with Pt and/or another metal.Such a catalyst can be modified (impregnated) with a hydrogenation metalsuch as Pt, Pd, another Group VIII metal, a Group VIB metal, or amixture of such metals. In an embodiment, the amount of hydrogenation(e.g., Group VIII) metal can be at least 0.1 wt %, based on the totalcatalyst weight, for example at least 0.5 wt % or at least 0.6 wt %. Insuch embodiments, the amount of hydrogenation metals can be 1.0 wt % orless, for example 0.9 wt % or less, 0.75 wt % or less, or 0.6 wt % orless. Additionally or alternately, the amount of hydrogenation metals,either individually or in mixtures, can be at least 0.1 wt %, forexample at least 0.25 wt %, at least 0.5 wt %, at least 0.6 wt %, atleast 0.75 wt %, or at least 1 wt %. Additionally or alternately inthese embodiments, the amount of hydrogenation metals, eitherindividually or in mixtures, can be 35 wt % or less, for example 20 wt %or less, 15 wt % or less, 10 wt % or less, or 5 wt % or less.

In an embodiment, the hydrofinishing stage can be performed in the samereactor as the isomerization/dewaxing, e.g., with the same treat gasflow and at a contiguous (roughly the same) temperature. Additionally oralternately in some embodiments, stripping does not occur between thehydrofinishing and catalytic isomerization/dewaxing stages.

Diesel Product Properties

The diesel fuel produced by the above processes can have improvedcharacteristics relative to diesel fuel produced by otherisomerization/dewaxing processes. The diesel fuel product can have acetane value (ASTM D976) of at least about 50, for example at leastabout 55, at least about 60, or at least about 65. Additionally oralternately, the diesel fuel product can have a cetane index (ASTMD4737) of at least about 50, for example at least about 55, at leastabout 60, or at least about 65. Additionally or alternately, the dieselfuel product can have an n-paraffin content of less than about 10% byweight, for example less than about 8 wt %, less than about 6.5 wt %, orless than about 5 wt %. Additionally or alternately, the cloud point ofthe diesel fuel product can be about −30° C. or less, for example about−35° C. or less or about −40° C. or less.

Additional Embodiments

Additionally or alternately, the present invention includes thefollowing embodiments.

Embodiment 1

A method for producing a diesel fuel, comprising: mixing a biocomponentfeed portion having an oxygen content of at least about 8 wt % with amineral feed portion to form a combined feedstock, the combinedfeedstock having a sulfur content of less than about 50 wppm and anitrogen content of less than about 20 wppm, the biocomponent feedportion being at least about 5 wt % of the combined feedstock; andcontacting the combined feedstock with an isomerization/dewaxingcatalyst, the isomerization/dewaxing catalyst comprising (i) a molecularsieve selected from ZSM-23, ZSM-48, and a combination thereof and havinga silica to alumina ratio of about 90:1 or less, and (ii) ahydrogenation metal, under effective isomerization/dewaxing conditionsincluding a temperature of at least about 350° C. and being effective toremove about 99% of the oxygen content of the combined feed and toproduce an isomerized/dewaxed product having a cloud point of about −20°C. or less.

Embodiment 2

A method for producing a diesel fuel, comprising: mixing a biocomponentfeed portion having an oxygen content of at least about 8 wt % with amineral feed portion to form a combined feedstock, the biocomponent feedportion being at least about 5 wt % of the combined feedstock; andcontacting the combined feedstock with an isomerization/dewaxingcatalyst, the isomerization/dewaxing catalyst comprising (i) a molecularsieve selected from Beta, USY, ZSM-5, ZSM-35, ZSM-23, ZSM-48, and acombination thereof and (ii) at least about 2 wt % of a Group VIIIhydrogenation metal selected from Ni and/or Co plus at least about 10 wt% of a Group VIB hydrogenation metal selected from Mo and/or W, undereffective isomerization/dewaxing conditions including a temperature ofat least about 350° C. and being effective to remove about 99% of theoxygen content of the combined feed and to produce an isomerized/dewaxedproduct having a cloud point of about −20° C. or less.

Embodiment 3

A method for producing a diesel fuel, comprising: mixing a biocomponentfeed portion with a mineral feed portion to form a combined feedstock,the combined feedstock having a sulfur content of less than about 50wppm and a nitrogen content of less than about 20 wppm, the biocomponentfeed portion containing triglycerides, being substantially free ofketones, and having an oxygen content of at least about 8 wt %, thebiocomponent feed portion being at least about 5 wt % of the combinedfeedstock; and contacting the combined feedstock with anisomerization/dewaxing catalyst comprising at least 0.5 wt % of Pt as ahydrogenation metal and ZSM-48 having a silica to alumina ratio of about90:1 or less, under effective isomerization and/or dewaxing conditionsincluding a temperature of at least about 350° C. and being effective toremove about 99% of the oxygen in the combined feed and to produce adewaxed product having a cloud point of about −20° C. or less, whereinthe isomerized and/or dewaxed product exhibits a peak characteristic ofa ketone in an infrared spectrum between about 1700 cm⁻¹ and about 1725cm⁻¹.

Embodiment 4

The method of embodiment 1, wherein the hydrogenation metal comprises atleast one Group VIII metal selected from Pt and/or Pd in an amount of atleast about 0.5 wt %, based on the total weight of theisomerization/dewaxing catalyst.

Embodiment 5

The method of embodiment 1 or embodiment 4, wherein the hydrogenationmetal comprises at least about 2 wt % of Ni and at least about 10 wt %of W, Mo, or a combination thereof.

Embodiment 6

The method of embodiment 2, wherein the molecular sieve is selected fromZSM-23, ZSM-48, and combinations thereof.

Embodiment 7

The method of any of the previous embodiments, wherein the mineral feedportion is hydrotreated by contacting with a hydrotreating catalystincluding at least one hydrogenation metal under effective hydrotreatingconditions.

Embodiment 8

The method of embodiment 7, wherein (i) the effective hydrotreatingconditions are selected so as to yield a sulfur content from about 100wppm to about 500 wppm prior to mixing with the biocomponent feedportion; (ii) the hydrotreating comprises contacting the mineral portionof the feedstock with a hydrotreating catalyst in the presence ofhydrogen gas to produce a hydrotreated mineral portion of the feedstockand a gas phase effluent containing H₂S, and wherein contacting thecombined feedstock with the isomerization/dewaxing catalyst furthercomprises contacting at least a portion of the gas phase effluent fromthe hydrotreatment with the isomerization/dewaxing catalyst; or (iii)both (i) and (ii).

Embodiment 9

The method of embodiment 7 or embodiment 8, wherein the effectivehydrotreating conditions include a temperature of about 315° C. to about425° C., a total pressure of about 300 psig (about 2.1 MPag) to about3000 psig (about 21 MPag), an LHSV of about 0.2 hr⁻¹ to about 10 hr⁻¹,and a hydrogen treat gas rate of about 500 scf/bbl (about 84 Nm³/m³) toabout 10000 scf/bbl (about 1700 Nm³/m³).

Embodiment 10

The method of any one of embodiments 7-9, further comprising strippingthe hydrotreated feedstream prior to isomerization/dewaxing.

Embodiment 11

The method of any one of embodiments 7-10, wherein one or more of thefollowing is satisfied: (a) the combined feedstock containing thehydrotreated mineral feed portion is cascaded to theisomerization/dewaxing step without intermediate separation; (b) theeffective isomerization/dewaxing conditions include a temperature of atleast about 370° C.; (c) the biocomponent feed portion includes a fatand/or oil whose source is at least one of vegetable, animal, fish, andalgae; (d) the biocomponent portion is not hydrotreated prior toisomerization/dewaxing; (e) wherein the isomerized and/or dewaxedproduct is hydrofinished under effective hydrofinishing conditions; and(1) the molecular sieve has a silica to alumina ratio of about 75:1 orless.

Embodiment 12

The method of any one of the previous embodiments,

wherein the effective catalytic isomerization/dewaxing conditionsinclude a total pressure of about 400 psig (about 2.8 MPag) to about1500 psig (about 10.3 MPag), an LHSV of about 0.5 hr⁻¹ to about 5.0hr⁻¹, and a treat gas rate of about 500 scf/bbl (about 84 Nm³/m³) toabout 2000 scf/bbl (about 340 Nm³/m³).

Example of a Reaction System

A reaction system suitable for carrying out the above processes is shownschematically in FIG. 1. In FIG. 1, a mineral hydrocarbon feedstock 110can be introduced into a first hydrotreatment reactor 120. A hydrogentreat gas stream 115 can also be introduced into hydrotreatment reactor120. The mineral hydrocarbon feedstock can be exposed to hydrotreatingconditions in first hydrotreatment reactor 120 in the presence of one ormore catalyst beds that contain hydrotreating catalyst. Preferably, thehydrotreatment can reduce the sulfur content of the treated feedstock toabout 50 wppm or less, for example about 10 wppm or less, about 5 wppmor less, or about 3 wppm or less. Additionally or alternately, thehydrotreatment can preferably reduce the nitrogen content of the treatedfeedstock to about 10 wppm or less, for example about 5 wppm or less orabout 3 wppm or less. The hydrotreated feedstock 118 can optionally flowfrom hydrotreatment reactor 110 into a separation device 125, where gasphase products can be separated from liquid phase products. The liquidoutput 128 from separation device 125 can then be combined withbiocomponent feedstock 112.

In an alternative embodiment, hydrotreatment reactor 120 and separationdevice 125 can be omitted. In such an embodiment, the mineralhydrocarbon feedstock 110 can pass directly into conduit 128 forcombination with biocomponent feedstock 112. Also in such an embodiment,preferably both the mineral feed 110 and the biocomponent feed 112 canbe previously hydrotreated. In another alternative embodiment,biocomponent feedstock 112 can be introduced into hydrotreatment reactor120. In such an embodiment, (a) the biocomponent feed can be mixed withthe mineral feed prior to entering hydrotreatment reactor 120, (b) thefeeds can mix upon entering the reactor, or (c) the biocomponent feedcan be introduced into the second or later stage of a reactor containingmultiple hydrotreatment stages.

In various embodiments, the (hydrotreated) mineral hydrocarbon feedstock128 can be combined with biocomponent feedstock 112 prior to enteringisomerization/dewaxing reactor 140. The combined feedstock can beexposed to catalytic isomerization/dewaxing conditions in the presenceof one or more catalyst beds that contain an isomerization/dewaxingcatalyst.

The effluent 148 from catalytic dewaxing can optionally be hydrofinishedin a hydrofinishing stage 160. Depending on the configuration, eithereffluent 148 or effluent 168 can be considered as a hydroprocessedproduct for further use and/or processing.

HYDROPROCESSING EXAMPLES

A series of processing runs were performed to determine the catalystactivity and resulting products from treating feedstocks with variousisomerization/dewaxing catalysts. Table 1 provides a description of 4such catalysts.

TABLE 1 Hydrogenation Molecular Hydrogenation Metal amt. approx. SieveMetal (wt %) Si:Al ratio Catalyst 1 Beta Pt ~0.6 Catalyst 2 ZSM-23 Pt~0.6 Catalyst 3 ZSM-48 Pt ~0.6 Less than about 75:1 Catalyst 4 ZSM-48NiW Ni ~3; Less than about W ~13.8 75:1

The catalysts in Table 1 were used for hydroprocessing of variousmixtures of mineral and biocomponent feed. For all of the mixtures ofbiocomponent and mineral feed, a hydrotreated diesel fuel product wasused as the mineral feed. The hydrotreated diesel fuel was mixed witheither a non-hydrotreated soybean oil (a feed including triglycerides)or a non-hydrotreated fatty acid methyl ester formed from rapeseed oil.

Table 2 shows a series of reaction conditions that were runconsecutively. Each of Catalysts 1-4 were exposed to these conditions inseparate runs. For each of the runs below, the reaction pressure wasabout 600 psig (about 4.1 MPag). The treat gas rate was between about2100 scf/bbl (about 350 Nm³/m³) and about 2300 scf/bbl (about 390Nm³/m³) of pure (−100%) hydrogen.

As indicated in Table 2, test conditions 4, 5, 7, 8, and 9 correspond tocombined feeds that include both biocomponent and mineral portions. Testconditions 1, 2, 6, and 10 correspond to the hydrotreated diesel fuel(mineral portion only). Test condition 3 corresponds to the hydrotreatedvegetable oil (biocomponent portion only).

TABLE 2 Test Reaction T LHSV condition Feed (° C.) (hr⁻¹) 1 100% mineraloil 349 3.3 2 100% mineral oil 332 3.3 3 100% hydrotreated vegetable oil332/349 2.6 4 50 wt % RME/50 wt % mineral oil 349 3.0 5 50 wt % RME/50wt % mineral oil 349 1.9 6 100% mineral oil 349 1.9 7 10 wt % RME/90 wt% mineral oil 371 1.9 8 20 wt % veg oil/80 wt % mineral oil 371 1.9 9 20wt % veg oil/80 wt % mineral oil 349 1.9 10 100% mineral oil 349 3.3

Cloud point results for the various processing runs are shown in FIG. 2.FIG. 2 displays cloud point measurements versus number of days on oilfor processing runs using Catalysts 1-4. In FIG. 2, numbers are used toindicate the test condition corresponding to each processing area. Thedotted line in FIG. 2 shows the cloud point prior to processing for eachof the feeds. The various shapes show the results after processing foreach catalyst. As indicated in FIG. 2, diamonds correspond to Catalyst1, circles correspond to Catalyst 2, triangles correspond to Catalyst 3,and squares correspond to Catalyst 4.

Catalysts 1 and 2

FIG. 2 shows that both Catalyst 1 and Catalyst 2 provided some cloudpoint reduction for deoxygenated biocomponent feeds. Test condition 3corresponds to a feed containing only hydrotreated vegetable oil. Theinitial cloud point for this feed was about 20° C. Exposing the feed toCatalyst 1 at a dewaxing temperature of about 349° C. resulted in aproduct with a cloud point between about 0° C. to about 5° C. A similarprocess using Catalyst 2 resulted in a product with a cloud pointbetween about −10° C. and −5° C.

Catalyst 3

Catalyst 3 was generally effective for isomerization of mineral feeds,as shown in FIG. 2. In test conditions 1 and 2, Catalyst 3 resulted incloud point improvements of about 20° C. to 40° C., relative to thefeed, with some dependence on the processing temperature. Catalyst 3performed similarly for the previously hydrotreated vegetable oil oftest condition 3. At the higher processing temperature of about 349° C.,exposing the hydrotreated vegetable oil to Catalyst 3 resulted in aproduct having a cloud point between about −25° C. and −35° C. Thiscorresponds to a cloud point reduction of more than about 40° C., ormore than about 50° C., relative to the feed cloud point of about 20° C.This is comparable to the cloud point reduction achieved for a mineralfeed processed at about 349° C. in test condition 1.

Applicants also note that there is some variation in the data for thevarious mineral feed only conditions, corresponding to test conditions1, 2, 6, and 10. In particular, test condition 6 occurs twice. In bothinstances, test condition 6 shows a lower activity for catalyst 3.Additionally, the activity for cloud point reduction in the secondoccurrence of test condition 6 is slightly higher than for the firstoccurrence.

Without being bound by any particular theory as to cause, Applicantsnote that the presence of biocomponent portions in test conditions 4, 5,7, 8, and 9 resulted in generation of water. Water can potentiallyimpact catalyst activity in a couple of ways. One impact could be somelevel of catalyst poisoning due to the presence of the water. It isnoted that the first occurrence of test condition 6 was immediatelyafter test conditions using about 50 wt % of biocomponent feed. Thistest condition showed the least catalyst activity for cloud pointreduction. Prior to the second occurrence of test condition 6, abiocomponent feed with only about 20 wt % biocomponent was used. Testcondition 6 showed a somewhat greater activity for cloud pointreduction. The catalyst appeared to further recover in the testcondition 10, which was also a mineral feed. Another impact of the watercould be due to catalyst degradation. After the full series of testconditions were completed, this particular catalyst sample wasinspected. The bound catalyst particles appeared to have broken downinto significantly finer pieces. This may have been due to degradationof the catalyst binder due to the presence of excess water.

Catalyst 4

Under test condition 3, Catalyst 4 had only a modest impact on the cloudpoint of the hydrotreated vegetable oil. As shown in FIG. 2, processingwith Catalyst 4 resulted in a cloud point reduction of only about 5° C.at both temperatures (about 332° C. and about 349° C.). It is noted thatCatalyst 4 appeared to have higher activity at temperatures above about370° C., based on the results from test conditions 8 and 9. Thus,processing at higher temperatures could improve the cloud pointreduction activity of Catalyst 4.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For this reason, then, reference shouldbe made solely to the appended claims for purposes of determining thetrue scope of the present invention.

1. A method for producing a diesel fuel, comprising: mixing abiocomponent feed portion having an oxygen content of at least about 8wt % with a mineral feed portion to form a combined feedstock, thecombined feedstock having a sulfur content of less than about 50 wppmand a nitrogen content of less than about 20 wppm, the biocomponent feedportion being at least about 5 wt % of the combined feedstock; andcontacting the combined feedstock with an isomerization/dewaxingcatalyst, the isomerization/dewaxing catalyst comprising (i) a molecularsieve selected from ZSM-23, ZSM-48, and a combination thereof and havinga silica to alumina ratio of about 90:1 or less, and (ii) ahydrogenation metal, under effective isomerization/dewaxing conditionsincluding a temperature of at least about 350° C. and being effective toremove about 99% of the oxygen content of the combined feed and toproduce an isomerized/dewaxed product having a cloud point of about −20°C. or less.
 2. The method of claim 1, wherein the hydrogenation metalcomprises at least one Group VIII metal selected from Pt and/or Pd in anamount of at least about 0.5 wt %, based on the total weight of theisomerization/dewaxing catalyst.
 3. The method of claim 2, wherein theeffective isomerization/dewaxing conditions include a temperature of atleast about 370° C.
 4. The method of claim 1, wherein the hydrogenationmetal comprises at least about 2 wt % of Ni and at least about 10 wt %of W, Mo, or a combination thereof.
 5. The method of claim 1, whereinthe biocomponent feed portion includes a fat and/or oil whose source isat least one of vegetable, animal, fish, and algae.
 6. The method ofclaim 1, wherein the effective catalytic isomerization/dewaxingconditions include a total pressure of about 400 psig (about 2.8 MPag)to about 1500 psig (about 10.3 MPag), an LHSV of about 0.5 hr⁻¹ to about5.0 hr⁻¹, and a treat gas rate of about 500 scf/bbl (about 84 Nm³/m³) toabout 2000 scf/bbl (about 340 Nm³/m³).
 7. The method of claim 1, whereinthe mineral feed portion is hydrotreated under effective hydrotreatingconditions prior to mixing with the biocomponent feed.
 8. The method ofclaim 7, wherein the effective hydrotreating conditions include atemperature of about 315° C. to about 425° C., a total pressure of about300 psig (about 2.1 MPag) to about 3000 psig (about 21 MPag), an LHSV ofabout 0.2 hr⁻¹ to about 10 hr⁻¹, and a hydrogen treat gas rate of about500 scf/bbl (about 84 Nm³/m³) to about 10000 scf/bbl (about 1700Nm³/m³).
 9. The method of claim 7, further comprising stripping thehydrotreated feedstream prior to isomerization/dewaxing.
 10. The methodof claim 7, wherein the combined feedstock containing the hydrotreatedmineral feed portion is cascaded to the isomerization/dewaxing stepwithout intermediate separation.
 11. The method of claim 1, wherein theisomerized and/or dewaxed product is hydrofinished under effectivehydrofinishing conditions.
 12. The method of claim 1, wherein thebiocomponent portion is not hydrotreated prior toisomerization/dewaxing.
 13. A method for producing a diesel fuel,comprising: mixing a biocomponent feed portion having an oxygen contentof at least about 8 wt % with a mineral feed portion to form a combinedfeedstock, the biocomponent feed portion being at least about 5 wt % ofthe combined feedstock; and contacting the combined feedstock with anisomerization/dewaxing catalyst, the isomerization/dewaxing catalystcomprising (i) a molecular sieve selected from Beta, USY, ZSM-5, ZSM-35,ZSM-23, ZSM-48, and a combination thereof and (ii) at least about 2 wt %of a Group VIII hydrogenation metal selected from Ni and/or Co plus atleast about 10 wt % of a Group VIB hydrogenation metal selected from Moand/or W, under effective isomerization/dewaxing conditions including atemperature of at least about 350° C. and being effective to removeabout 99% of the oxygen content of the combined feed and to produce anisomerized/dewaxed product having a cloud point of about −20° C. orless.
 14. The method of claim 13, wherein the effectiveisomerization/dewaxing conditions include a temperature of at leastabout 370° C.
 15. The method of claim 13, wherein the molecular sieve isselected from ZSM-23, ZSM-48, and combinations thereof.
 16. The methodof claim 15, wherein the molecular sieve has a silica to alumina ratioof about 75:1 or less.
 17. The method of claim 13, wherein the mineralfeed portion is hydrotreated by contacting with a hydrotreating catalystincluding at least one hydrogenation metal under effective hydrotreatingconditions so as to yield a sulfur content from about 100 wppm to about500 wppm prior to mixing with the biocomponent feed portion.
 18. Themethod of claim 17, wherein the hydrotreating comprises contacting themineral portion of the feedstock with a hydrotreating catalyst in thepresence of hydrogen gas to produce a hydrotreated mineral portion ofthe feedstock and a gas phase effluent containing H₂S, and whereincontacting the combined feedstock with the isomerization/dewaxingcatalyst further comprises contacting at least a portion of the gasphase effluent from the hydrotreatment with the isomerization/dewaxingcatalyst.
 19. The method of claim 13, wherein the biocomponent portionis not hydrotreated prior to isomerization/dewaxing.
 20. A method forproducing a diesel fuel, comprising: mixing a biocomponent feed portionwith a mineral feed portion to form a combined feedstock, the combinedfeedstock having a sulfur content of less than about 50 wppm and anitrogen content of less than about 20 wppm, the biocomponent feedportion containing triglycerides, being substantially free of ketones,and having an oxygen content of at least about 8 wt %, the biocomponentfeed portion being at least about 5 wt % of the combined feedstock; andcontacting the combined feedstock with an isomerization/dewaxingcatalyst comprising at least 0.5 wt % of Pt as a hydrogenation metal andZSM-48 having a silica to alumina ratio of about 90:1 or less, undereffective isomerization and/or dewaxing conditions including atemperature of at least about 350° C. and being effective to removeabout 99% of the oxygen in the combined feed and to produce a dewaxedproduct having a cloud point of about −20° C. or less, wherein theisomerized and/or dewaxed product exhibits a peak characteristic of aketone in an infrared spectrum between about 1700 cm⁻¹ and about 1725cm⁻¹.